Production of n-tertiary alkylated aromatic secondary diamines



Patented Oct. 19, 1954 PRODUCTION OF N-TERTIARY ALKYLATED AROMATICSECONDARY DIAIVEINES Alan Bell and M B Knowles, Kingspcrt, Tenn,assignors to Eastman Kodak Company, Rochester, N. Y., a corporation ofNew Jersey No Drawing. Application March 29, 1951, Serial No. 218,261

12 Claims.

This invention relates to di-tertiary-alkyl aromatic diamines andmethods for production thereof. More particularly, it relates toalkylations in which tertiary alkyl groups containing 4 to 8 carbonatoms are substituted in amine groups of aromatic diamines to producesecondary amine groups. It especially contemplates the preparation of N,N-di-tertiary-butyl-p-phenylene-diaznine by the reaction of p-phenylenediaznine with tertiary-butyl alcohol.

It is known to react primary and secondary alcohols with primaryaromatic amines to form corresponding N-alkyl substituted amines. Unlessvery special conditions of reactions are observed, however, the tertiaryamines are formed in these processes, that is, dialkylation of the aminegroup takes place. In addition, alkylation of the aromatic nucleus maybe eiiected particularly if elevated temperatures are employed. Thus, amixture of products is obtained, reducing the yield of monoalkylatedamine product, and necessitating the use of special separationprocedures to remove the secondary amine product (monoalkylated) fromthe tertiary amine product (dialkylated), the unreacted primary amine,and any nuclearly alkylated amine prodnote.

In past proposals, tertiary amine products are always obtained whenlarge mole ratios of primary or secondary alcohols to primary aromaticamines or their hydro-halide salts are employed in the reaction. Then toobtain secondary amines from primary amines by alkylation, this ratiohas been kept generally at 2 to 1 or lower. Even at these low ratiosunless special conditions of reaction are observed, dialkylated ortertiary amines result. For example, Staedel, German Patent 21,241,dated February 3, 1882, obtained near quantitative yields ofN,N-diethyl-aniline, N,N-diethylorthotoluidine andN,N-diethylparatoluidine by heating ethyl alcohol with thecorrespondingprimary amine hydroiodides at 145 C. to 150 C. In theseprocedures the mole ratio of ethyl alcohol to amine was kept at 1.1to 1. Essentially the same results were obtained when the aminehydrobromides were employed. Reilly and Hickinbottom, J. Chem. Soc. 113,102,976 (1918) obtain the products N-monobutylaniline,N,N-dibutylani1ine and p-butylaniline from the reaction of anilinehydrochloride with normal butyl alcohol. Finally Carleton et al., in U.S. Patent 1,994,852 obtained mixtures of mono-N- alkylated anddi-N-alkylated aromatic amines using primary and secondary alcohols byfollow ing restricted conditions such as first forming a partial aminesalt by reaction of a mole of primary amine with 0.6 to 0.9 mole ofhydrochloric acid and then alkyltaing with 1.9 to moles of a primary orsecondary alcohol. In our process for the preparation of N-tertiaryalkylated aryldiamines, we obtain no complexity of products. Good yieldsof the secondary amine products are obtained without formation oftertiary amine products even where very highv mole ratios of tertiaryalcohols to primary aromatic diaznines is employed. in addition, we havefound no nuclearly alkylated aromatic diamine products and we havediscovered that we do not have to limit our mole ratio of mineral acidcatalyst to amine group at 0.6:1 to 0.9-:1; in fact, our preferredconditions for reaction, as will be described hereinaiter, call for amole ratio of tertiary alcohol to diamine of greater than 4:1 and aratio of hydrohalogenic acid to primary amine equivalent of 1:1.

Tertiarybutyl alcohol and other tertiary alcohols have not been employedheretofore in the preparation of N-alkylated aromatic amines. It was tobe expected prior to our discovery that excessive dehyration of thetertiary alcohol would result under the conditions of reaction and itwas also expected that mixtures of secondary and tertiary amine productswould result. The methods employed in the past to prepareN-tertiary-butylaniline for example, call for the use of aniline andtertiary-butyl iodide. This procedure which is described byHiclrinbottom, J. Chem. Soc. 1933, 946, is attended with certaindeficiencies, such as low yields of desired product, instability oftertiary-alkyl iodides under basic conditions, and the use oftertiary-alkyl iodides which are relatively expensive laboratoryreagents. Hickinbottoms process, although well adapted for laboratorypreparation, cannot be considered of commercial utility in View of thelast-mentioned feature. Further, we have found this reaction to be sohighly exothermic, that reduced yields of prodnot are obtained whenlarge amounts of reactants are used. Finally we have carried outnumerous experiments following the procedures of Hici inbottom and alsoNef, Analen 309, 164 and have been unable to prepareN,N-ditertiary-alkylaromatic-diamines such asN,N'-ditertiary-butylphenylenediamine by the use of these methods.

A principal purpose of this invention is to provide a new and improvedmethod for producing,

N tertiary alkylated aromatic secondary diamines. Another object is theproduction of NH- di-tertiary-alkyl aromatic diamines particularly thosewith tertiary-alkyl groups containing 4- to 8 carbon atoms by an easilycontrolled process which is characterized by its flexibility. A furtherobject is the production of oxygen-resistant and color-stableN,N'-di-tertiary-butyl-p-phenylenediamine. A still further object of theinvention is the production of tertiary-alkylated secondary diaminesfrom primary diamines in such a manner that the reaction productcontains no tertiary-alkylated-tertiary amine groups, or in other words,that the primary amine groups of the aromatic diamine are mono-alkylatedand not dialkylated by the process. Other objects of the invention willbecome apparent hereinafter.

These objects are accomplished according to the invention wherebyN,N'-di -tertiary-alkyl aromatic diamines are produced from aromaticdiamines with a tertiary-alkyl alcohol and in the presence of acidcatalysts selected from the group HCl, HBr, HI, alone or in conjunctionwith small amounts of iodine, or the dehydrating mineral acid catalystssulfuric acid or the oxy-acids of phosphorus in con-jilnction withiodine, or in the presence 'of catalytic amounts of iodine alone. Thereaction takes place under conditions of elevated temperature and"pressure. The NH- di-tertiary-alkyla'ted diamine i'na'y be recovered inany suitable manner, and unreacted primary diamine and partially reacteddiamine reprocessed. The tertiary-alkylated diam'ines so produced areuseful as antioxidants or stabilizers for petroleum products andpolymeric materials such as rubber. The 'N,N'di-tertiary-butylatedaromatic diamines are particularly'us'eful in that the amine groups are"stable to the effects or air and light and the compounds retain good'ml'or as compared with corresponding primaryor secondary-alkylatedaromatic 'diamines.

According to a preferred embodiment, the invention is applied to thealkylation of p-phenylene diamine, in the form of the aminehydrochloride salt, by reacting the amine salt with tertiary-butylalcohol in the presence of a small amount of iodine; under autogen'ouspressure and at elevated temperature, the reaction being so controlledas to produce'only the N,N-di-tertiary butyl-"p-phenyle'ne 'diamine, andnot the N,N,N,N-tetra-tertiary-butyl p 'phenylene diamine, nor theN,N,N' tri tertiary butyl 'pphenylene diamin'e.

The following'examples will serve to illustrate our process.

Example 1 .-N,N' -di-tertz'ary-butyZ-p-phenylenediamine One hundred andninety-three parts of phenylenediamine were combined with 49 parts ofhydrogen chloride and then heated together with 495 parts of tertiarybutyl'alcohol for 5 hours at 180 C. The reaction mixture was-taken upwith water and made basic with concentrated ammonium hydroxide solutionfollowed by extraction with ether. The extract was dried, the solventremoved, and the residue distilled. The distillate of boiling-range 116to 135'C./ 3'mm., was suspended in water and treated with aceticanhydride. The excess acetic 'anhydride used was allowed to hydrolyze.The mixture was filtered, made basic with sodium carbonateandextractedwith ether. Fractionation of extracted material gave 17.7 parts B. P.106.5 to '139/1-"3 mm. 6.7 parts'of white-crystalline sol-id MQP.11-7955 0. were obtained when the distillate wascrystallized twice froma water alcoholmixture. This product analyzed forN,N'-di-tertiary-butyl-p-'phenylenediamine giving C, 76:45, E, 11.04, N,12.25,

whereas calculated analysis for 01'4H24N2 is *0,

76.31, H, 10.98, N, 12.72. Further proof of identity was made bypreparing N,N' dinitroso derivative of M. P. 210212 C., which analyzedfor C14H22N402 and by oxidizing the product with chromic acid to 1,4benzoquinone.

Example '2.-N;N -di-tertiarybutyl-p-phenylenediamz'ne A mixture of 2700parts of tertiary-butyl alcohol, 650 parts of p-phenylenediaminehydrochlo ride, and 0.5 parts of iodine were heated for 5 hours at170-180 C. in a rocking steel autoclave. The reaction mixture was washedout of the autoclave with 1000 parts of water and a large quantity ofsolid present was separated from this Water mixture. This solid wasdissolved in 1500 parts of water and the resulting solution was madebasic with concentrated ammonium hydroxide solution to give a greycrystalline material melting at 77-79" "C. y

The water solution from the autoclave, after removal of theabove-mentioned solid, was distilled to remove unreacted tertiary-butylalcohol. The residue was made'basic withammonium hydroxide solution anda dark oily product was obtained. This was dissolved in dilute aceticacid and shaken with 20 parts of 'benzaldehyde to remove anyN-tertiary-butyl-p-phenylenediamine or other primary amines present. Themixture was extracted with ether, ammonium hydroxide was added and agrey crystalline material melting at 79-80 C. was obtained.

The two crystalline products were combined and distilled to obtain-1'33parts of product boiling at 289-291 C. and melting at 77-785 C.Analysis for carbon, hydrogen and nitrogen of this compound and of itsdinitroso-derivative indicated that it was 'N,N' di=-tertiary-butyl-pphenylenediamine. In-additionoxidation of the productwith chromic acid produced p-berizoquinone.

Example 3.N, N -di-tertiary-butyZ-m-phenylenediamine One hundred partsof m-pheny'lenediamine, 410 parts of tertiary-butyl alcohol and 0.5.parts of iodine were heated together at 170-180 C. for five hours. Thereaction products were then added to 800 parts of water and distilled toremove unreacted tertiary butyl alcohol. The mixture was extracted withether and the'extract was discarded. After being 'madeibasic withconcentrated ammonium hydroxide, the .mixture again was extracted withether. The ether 'extract'was dried, the solvents were removed, and theresidue distilled. There was obtained 53 parts of product boiling at212-229 C. (80 'mm.). order to remove the primary aminespresent'su'ch asN tertiary butyl --m-phenylenediamine, the product was covered with 150parts of water and 40 parts of glacial acetic acid. A white solidformed, although most of the material "redissolved. This solid wascollected and dried; the yield was 8 parts ofN-N'-di-tertiary-butyl-mphenylenediamine melting at 156-157 G. The

formula C14H24N2, calculates for 0,7631; H, 10.98; N, 12.73. Analysis of'thisproduct gave C, 76.42; H, 10.95; N, 12.74.

Example 4.N-tertiary-butyl-2;4-diaminotoluene Tertiary butyl alcohol(480 parts) 2,4-diaminotoluene dihydrochloride (parts),and iodine (0.5parts) were heated in a-shaking type steel 1 autoclave for five hours atC. The reaction mixture was poured into 1000 parts of water and Iamazes: n

unreacted alcohol was removed by boiling.- The the production": of Nflvdi-tertiary alliylated di solution was cooled, made basic with sodiumamines; N-tertiary-alkyl'ated diamines arepro carbonate and extractedwith ether. The ether duced in-the' process and maybe separated-aswas"removed, the residue dissolved in 700 parts such, andin the case whereone amine group is of water containing 80 parts of acetic acid andhindered by ortho'sub'stitution as' in Example the solution shaken with80 parts of benzalde- 4, theend productbf alkylation may be the: N

hyde for five minutes. After extracting with tertiary-aHcyla-teddiamine. Generally,- where ether, the aqueous portion was made basicand. both amine groups can bealk-ylated', we prefer the oil layerremoved with ether. The extract not toiseparate mono-alkylated productfrom the was dried and the solvent removed leaving 34 reaction products;but to use -it and the unreactecls parts ofa.brown oil whichcrystallizedupon primary amine as reactants for preparingmorestanding.Aftertwo recrystallizations from hex-- N,N"-di-tertiary-alkylatedaromatic diamines; ane, it melted at 56 .6 to 58 C. and analyzed for Themonoalkylated such as N-ter the mono tertiarybutyl derivative C11H18N2which tiary butyl p phenylenediamine are usecalculates C, 74.1; H,10.17; N, 15.72. The analy-- ful in preparation of mixed alkylatedamines, sis gave C, 74.18; H, 10.28; N, 14.8. The. material however,that is, thefree-primary amine group diazotizes readily and couples withbeta 'naphthol. can be alkylated with an n-alkyl group if desired,

Following the general processes outlined in the or the-monoalkylatedaromatied'ia-mines can beabove-examples, a series of preparations werecarused as reactants in the present invention in-- ried out-under a:variety of conditions.- The re-- stead of the 'diprimary amines; v sultsare indicated in Table I. In all cases listed,v In carrying out theinvention, itis'preierable' the product recovered is theN,N'-dialkylated: di to heat the reactants together in a closedvesselamlne. so that the-pressure ofthe reaction is-the autog-- TABLE Inegation 1 Quantity ofi h Conver- MI rand D- R t v v Catalyst 7 Tem- 0es iamine eac ed Moles and Alcohol Reacted Used Cagggst g gf siolefie[0.51.p-phcnylenediamlne [3] tert.-butyl alcohol 200 1[1]p-phenylened1amine [60] tort-butyl alcohol H 1 170' 2 Do [42]tert.-butyl alcohol H 170 2- [0:51p-phenylenediamine [2] tert.-buty1alcohol 160 8 Do l. [5].tert.-butyl alcohol 180' 2-- Do.- [3] tert=butylalcohol 190' 9 Do [3].d.lmethyletl1yl carbinoL 180 12' Do. [5]dlmethylneopentyl carbinoL. 180' 8- [0.5]-l,4-naphtha1ene diamine; 5tert.-butyl alcohol C1 190. 5 [0.5] p,p-dlaminoblphenyl [3] tert.-butylalcohol v 170' 10" While the invention should not be limited by. enouspressure produced" by the reaction mix the aboveexamples, it should beunderstood that. ture, thus the pressure produced will depend tothisinvention is limited'to the use of saturated a large extent on theproportions ofreactants tertiary. ailkyl alcohols inconjunction'with pripresent as wel-I'as-the temperature. When opmary aromatic diamines,andwhiletertiary butyl crating at high temperatures, sayabove 200 (3.,alcohol is. preferred for use in alkylations, the.considerabledecomposition oftertiary al-k-yl alcoprocess is. applicablein the employment of higher: hol to olefin may take place andthusele-vate the tertiary alcohols. and. is particularly useful H11pressuretc above 600 pounds per square-inch;

conjunction with tertiary alcohols containing 4 We-havefoundno'beneficial or detrimental eito 8:. carbon atoms. In general, theclass. of fect by operating at'high orlow pressures and, amines whichcan be..used.. in this process are. hence, we prefer to operate at theautogenous primary aromatic diamines Which may or may pressure of thereaction-although wemay-vent not to. be nuclearlysubstituted;Representative on" isobutylene'for example; or other" gases; or

substituents. which may be presenton the ring we may add pressurein theformof inertgases without adversely affecting the process are; alk'ylwithout unduly altering the preparation'of de- (preferably 1, to 8carbonatoms), aryl, cyclesired products:-

alkyl' (5 to 6-carbon atoms), nitro', hydroxy, halo- In the aboveexamples the time of rea'ction'in' gen, acyl, acyloxy, andalko-xygroups. These. every case is 5 hours. Actually the timeof'resubstituentsshould not be orthoto the amine action does notappearto be critical but rather group; to be alkylated, however; We havemade depends upon thegeometryof-the. reaction systheunexpectedzdiscovery that ortho substitution tem,thequantitiesof'materialsused; the amount tends to inhibit thealkylation of aromatic amine ofagitation of the reactants, and so on,andto groups; with tertiary. alcohols and may, entirely a lesser extentupon the natureof the reactants. prevent-the reaction from taking place,for in- We find'in-generalthe" reactions can be comstance, see Example4. By the. same principle, pleted in l-to 24 hours, and-the bulk oftherethe: two amine. groups; should not be.- ortho to actions arecompletedin at least five hours. The eachother. It is well known that in thealkylaoptimum time for reaction can be determined tion of monoamines:with primary; alcohols such empirically, very easily.

asethyl alcohol, vfor example, ortho substitution As can .beseenfromithe:resultsobtainedzin the seems to have little. effect on thereaction, and examples, a. variety ofiioatalystscanxbeemployed.compounds such as N,N-.diethyl-o-toluidine. can Thehydrohalogenic acids,.I-ICl, HBr or- H-Ica-nv be prepared without difficulty. e be used inratios ofsOJzl to.2.1:1.moles-per molee Although \this :invention is:d-irecteda.ima-i nly,-to of diamine, with.apreferredratiootz;1i. Iodineecan be employed as a catalyst alone in small amounts of .01 to based onthe weight of amine. A combination of hydrohalogenic acids inconcentrations mentioned above in combination with iodine in preferredamounts of about 0.05% to 2% is particularly useful to bring about goodconversions to secondary diamines. Dehydrating mineral acids such assulfuric acid and the oxy-acids of phosphorus such as phosphoric andphosphorous (0.1 to 4% based on amine) in combination with iodine (0.5to 2%) may also be used as catalysts but do not appear to be as usefulas the other catalysts mentioned. Too large a quantity of iodine maybring about excessive dehydration of the tertiary alcohol which, ofcourse, is undesirable. The same reason limits the use of largeproportions of sulfuric acid or the oxy-acids of phosphorus. Thepreferred catalysts are then the acids selected from the group HCl, HBrand HI alone or more preferably in conjunction with iodine. Of theseacids hydrochloric acid is the most desirable to use because of its costand ease of handling.

The acid catalysts may be added to the reaction mixture in a variety ofways, such as combined with part or all of the primary diamine as thehydrochloride for example, or as a solution or mixture with thetertiary-alkyl alcohol. Generally we prefer to use the amine saltsdirectly.

The mole ratio of tertiary alcohol to aromatic amine may be varied from2:1 to as high as 60 to 1 or higher as will be observed in Table I butmole ratios of greater than 4:1 are preferred with optimum results beingobtained at mole ratios of 5:1 to :1. Although a 60:1 ratio or evenhigher ratios bring about just as good conversions as this latteroptimum range, such high ratios only bring about waste of reactionvessel space.

The N-tertiary-alkylated secondary diamines can be prepared attemperatures of 150 C. to 220 C. The preferred temperature range is 170-190 C. Actually some alkylation may take place at temperatures as low as120 C. using preferred catalysts, but conversions are low. Attemperatures above 220 C. excessive dehydration of the tertiary alcoholmay take place.

The products prepared by this process as mentioned heretofore areespecially useful as antioxidants. In addition we have made thesurprising discovery that N,N'-di-tertiary butyl aromatic diamines areparticularly stable to the effect of atmospheric oxygen as compared withthe corresponding N,N'-secondary-alky1 or N,N'- di-normal-alkylderivatives. Thus the N-tertiary-butyl derivatives may be termed oxygenresistant. For example, N,N-di-tertiary-butylp-phenylenediamine can bemade into a 0.5% benzene solution and this solution exposed to daylightand air for two weeks Without coloration. Freshly prepared solution of0.5% N,N'-di-secondary-butyl-p-phenylenediamine is not quite colorlessand on exposure to light and air darkens rapidly in five or six days toproduce a dark brown colored solution.

The antioxidant value of N,N-di-tertiarybutyl-p-phenylenediamine ascompared with N,N'-di-secondary-butyl-p-phenylenediamine (a standardgasoline antioxidant) can be observed in Table II where a Pennsylvaniacracked gasoline was used in conjunction with these stabilizers in thestandard oxygen bomb test (U. 0. R).

The potency of the N,N-di-tertiary-butyl derivative is about the same asthe potency of the N,N-di-secondary-butyl derivative.

TABLE II.-U. O. P. OXYGEN BOMB TEST Induction Sample Period,

Minutes Cracked Gasoline 45 Cracked Gasoline+0.0l% N,N-disec.-butyl-pphenylenediamine 877 Cracked Gasoline+0.0l%N,N-di-iert.-butyl-p-phenylenediamine; 840

It will be observed from the examples that onlymono-tertiary-alkylaromatic amine groups are formed by this process, andnot the dialkylated amine groups or nuclearly alkylated products. Ofcourse, there may be varying amounts of unreacted primary amines presentin the crude products but this can be separated from the secondary amineproduct readily and reprocessed. The fact that no complexity ofalkylated products results is of commercial advantage since thesecondary amines have great practical use as stabilizers.

The invention is advantageous to use in that the only known priordisclosures for producing tertiary-alkylated amines which demand the useof tertiary-butyl iodide, are not found to be applicable to thproduction of iN,N-di-tertiary alkyl-aromatic diamines.

Processes of producing N-tertiary alkylated aromatic secondarymonoamines such as N- tertiary-butylaniline and the like are disclosedand claimed in our copending application Serial No. 218,262, filed oneven date herewith.

What we claim as our invention is:

1. A process for producing N-tertiary alkylated aromatic secondarydiamines which comprises reacting one mole proportion of a carbocyclicaromatic primary diamine with from 2 to 60 mole proportions of asaturated tertiary alkyl alcohol containing from 4 to 8 carbon atoms inthe presence of a catalyst at a temperature of from to 220 C., saidaromatic diamine containing from 6 to 15 carbon atoms wherein the NH2groups are in nuclear positions with respect to each other which areother than adjacent, the

aromatic diamine also containing nuclear substituents which are inpositions other than ortho to one of the NI-I2 groups, whichsubstituents are selected from the group consisting of a hydrogen atom,an alkyl radical containing from 1 to 8 carbon atoms, an aryl radicalcontaining from 6 to 9 carbon atoms, a cycloalkyl radical containingfrom 5 to 6 carbon atoms, a nitro radical, a hydroxy radical, a halogenatom, a -COR radical, a -CO-OR radical and an OR radical wherein each Rrepresents an alkyl radical containing from 1 to 8 carbon atoms, saidcatalyst comprising at least one material selected from among thosematerials of the following subgroups (A) from about 0.1 to about 1.1

mole proportions of H01, I-IBr and HI, (B) from about 0.01 to about 5%by weight based on the weight of the aromatic diamine of iodine, (C) acombination of a material defined by subgroup (A) and the materialdefined by subgroup (B), (D) a combination of the material as definedbysubgroup (B) and from about 0.1 to about 4% by weight based on theweight of the aromatic diamine of sulfuric acid, (E) a combination ofthe material defined by subgroup (B) and from about 0.1 to about 4% byweight based on the weight of the aromatic diamine of an oxyacid ofphosphorous.

2, A process according to claim 1 in which the 9 primary aromaticdiamine is paraphenylenediamine.

3. A process according to claim 1 in which the primary aromatic diamineis metaphenylenediamine.

4. A process according to claim 1 in which the primary aromatic diamineis 2,4-diaminotoluene.

5. A process according to claim 1 in which the primary aromatic diamineis 1,4-naphthalenediamine.

6. A process according to claim 1 in which the primary aromatic diainineis p,p-diaminobi" phenyl.

7. A process of producing N,N-di-tertiary butyl paraphenylenediaminewhich comprises reacting a mole proportion of paraphenylenediaminedihydrochloride with to mole proportions of tertiary butyl alcohol inthe presence of 0.5 to 2 per cent of iodine, based on the weight ofparaphenylenediamine present in the amine salt employed, at atemperature of 170 to 190 C.

8. A process of producing N,N-di-tertiary butyl metaphenylenediaminewhich comprises reacting a mole proportion of metaphenylenediaminedihydrochloride with 5 to 10 mole proportions of tertiary-butyl alcoholin the presence of 0.5 to 2 per cent of iodine, based on the weight ofmetaphenylenediamine present in the amine salt employed, at atemperature of 170 to 190 C.

9. A process of producing N-tertiary butyl- 2,4-diamino toluene whichcomprises reacting a mole proportion of 1,4-diaminotoluenedihydrochloride with 5 to 10 mole proportions of tertiarybutyl alcoholin the presence of 0.5 to 2 per cent of iodine based on the weight of2,4-diamino- 1f) toluene present in the amine salt employed, at atemperature of to C.

10. A process of producing N,N-di-tertiary butyl-lA-naphthalenediaminewhich comprises reacting a mole proportion of 1,4-naphthalenediaminedihydrochloride with 5 to 10 mole proportions of tertiary-butyl alcoholin the presence of 0.5 to 2 per cent of iodine based on the weight oflA-naphthalenediamine present in the amine salt employed, at atemperature of 170 to 199 C.

11. A process of producing N ,N'-di-tertiary butyl-p,p'-diaminobiphenylwhich comprises reacting a mole proportion of p,p-diaminobiphenyldihydrochloride with 5 to 10 mole proportions of tertiary-butyl alcoholin the presence of 0.5 to 2 per cent of iodine based on the weight ofp,p'-diaminobiphenyl present in the amine salt employed, at atemperature of 170 to 190 C.

12. A process according to claim 1 in which the saturated tertiary alkylalcohol is tertiary-butyl alcohol.

References Cited in the file of this patent UNITED STATES PATENTS NameDate Carleton et a1 Mar. 19, 1935 Andrews Mar. 16, 1937 Dickey et a1Dec. 18, 1945 Number OTHER REFERENCES

1. A PROCESS FOR PRODUCING N-TETIARY ALKYLATED AROMATIC SECONDARYDIAMINES WHICH COMPRISES REACTING ONE MOLE PROPORTION OF A CARBOCYCLICAROMATIC PRIMARY DIAMINE WITH FROM 2 TO 60 MOLE PROPORTIONS OF ASATURATED TERTIARY ALKYL ALCOHOL CONTAINING FROM 4 TO 8 CARBON ATOMS INTHE PRESENCE OF A CATALYST AT A TEMPERATURE OF FROM 150* TO 220* C. SAIDAROMATIC DIAMINE CONTAINING FROM 6 TO 15 CARBON ATOMS WHEREIN THE -NH2GROUPS ARE IN NUCLEAR POSITIONS WITH RESPECT TO EACH OTHER WHICH AREOTHER THAN ADJACENT, THE AROMATIC DIAMINE ALSO CONTAINING NUCLEARSUBSTITUENTS WHICH ARE IN POSITIONS OTHER THAN ORTHO TO ONE OF THE -NH2GROUPS, WHICH SUBSTITUENTS ARE SELECTED FROM THE GROUP CONSISTING OF AHYDROGEN ATOM, AN ALKYL RADICAL CONTAINING FROM 1 TO 8 CARBON ATOMS, ANARYL RADICAL CONTAINING FROM 6 TO 9 CARBON ATOMS, A CYCLOALKYL RADICALCONTAINING FROM 5 TO 6 CARBON ATOMS, A NITRO RADICAL, A HYDROXY RADICAL,A HALOGEN ATOM, A -CO-R RADICAL, A -CO-OR RADICAL AND AN -OR RADICALWHEREIN EACH R REPRESENTS AN ALKYL RADICAL CONTAINING FROM 1 TO 8 CARBONATOMS, SAID CATALYST COMPRISING AT LEAST ONE MATERIAL SELECTED FROMAMONG THOSE MATERIALS OF THE FOLLOWING SUBGROUPS (A) FROM ABOUT 0.1 TOABOUT 1.1 MOLE PROPORTIONS OF CHL, HBR AND HI, (B) FROM ABOUT 0.01 TOABOUT 5% BY WEIGHT BASED ON THE WEIGHT OF THE AROMATIC DIAMINE OFIODINE, (C) A COMBINATION OF A MATERIAL DEFINED BY SUBGROUP (B) (A) ANDTHE MATERIAL DEFINED BY SUBGROUP (B), (D) A COMBINATION OF THE MATERIALAS DEFINED BY SUBGROUP (B) AND FROM ABOUT 0.1 TO ABOUT 4% BY WEIGHTBASED ON THE WEIGHT OF THE AROMATIC DIAMINE OF SULFURIC ACID, (E) ACOMBINATION OF THE MATERIAL DEFINED BY SUBGROUP (B) AND FROM ABOUT 0.1TO ABOUT 4% BY WEIGHT BASED ON THE WEIGHT OF THE AROMATIC DIAMINE OF ANOXYACID OF PHOSPHOROUS.